Combined Echocardiography and Lung Ultrasound for Extubation Outcome Prediction in Children after Cardiac Surgery

Background:Children are at risk of extubation failure after congenital heart disease surgery.Such cases should be identified to avoid possible adverse consequences of failed extubation.This study aimed to identify ultrasound predictors of successful extubation in children who underwent cardiac surgery.Methods:Children aged 3 months to 6 years who underwent cardiac surgery(if they were intubated for>6 h and underwent a spontaneous breathing trial)were included in this study.Results:We included 83 children who underwent surgery for congenital heart disease.Transthoracic echocardiography and lung ultrasound were performed immediately before spontaneous breathing trials.Upon spontaneous breathing trial completion,respiratory parameters,including arterial blood gas analysis and frequency-to-tidal volume ratio,were similarly recorded.For outcome assessment,all children were followed up for 48 h after extubation.We successfully extubated 57 children(68.7%).These children were significantly older and weighed more but had shorter aortic cross-clamp and cardiopulmonary bypass times.Children who could not be weaned or extubated had prolonged total mechanical ventilation and pediatric intensive care unit stay.In the multivariate regression analysis,a lung ultrasound score≥12 and ejection fraction≥40%immediately before spontaneous breathing trials were the only independent predictors of successful extubation.When combined,the lung ultrasound score and an ejection fraction≥40%showed a better diagnostic performance than every other isolated variable(lung ultrasound,N-terminal-pro-B-type natriuretic peptide,and frequency-to-tidal volume ratio).Conclusions:The combination of lung ultrasound and transthoracic echocardiography immediately before the spontaneous breathing trial effectively predicts extubation outcomes in children after cardiac surgery.

Computer-driven automated weaning reduces weaning duration in difficult-to-wean patients

Background Weaning difficulties occur in 31% of total intubated patients, and result in prolonged weaning duration. A computer-driven automated weaning system can perform a spontaneous breathing trial （SBT） automatically and display a message when the trial is successfully passed. Such a system might have a beneficial effect on difficult-to-wean patients. The aim of this study was to examine whether the computer-driven automated weaning system can accelerate discontinuation of mechanical ventilation and improve outcomes in difficult-to-wean patients. Methods This randomized controlled study included 39 difficult-to-wean patients who failed their first spontaneous breathing trial. Before initiating weaning, eligible patients were randomly allocated to wean by computer-driven automated weaning system （CDW group, n=19） or a physician-controlled local protocol （PW group, n=20）. Weaning duration, defined as the time from inclusion until first extubation, was the primary endpoint. Secondary endpoints were total duration of mechanical ventilation, the length of intensive care unit （ICU） stay, the number of reintubations, the mortality rate in the ICU, the number of noninvasive ventilations, the number of complications in the ICU, and the number of ventilator-associated pneumonia cases. Results The weaning duration was reduced with the computer-driven weaning as compared with the usual protocol （median 29.0 hours vs. 45.5 hours, P=0.044）. Total duration of mechanical ventilation and duration of the ICU stay did not differ between the CDW and PW groups. There was no difference in the number of reintubations between the CDW and PW groups （3 and 4 patients, P=0.732）. The study groups showed comparable numbers of tracheostomy, self- extubations, ventilator-associated pneumonia, and non-invasive ventilation. Mortality in the ICU was similar in the CDW and the PW groups （21.1% vs. 20.0%, P=0.935）. Conclusion The computer-driven automated weaning system can reduce weaning duration in difficult-to-wean patients as compared with a physician-controlled weaninq protocol.

Oxygenation strategies after extubation of critically ill and postoperative patients

In intensive care units(ICUs),the decision to extubate is a critical one because mortality is particularly high in case of reintubation.Around 15%of patients ready to be weaned offa ventilator experience extubation failure leading to reintubation.The use of high-flow nasal oxygen and non-invasive ventilation are two alternatives of standard oxygen supplementation that may help to prevent reintubation.High-flow nasal oxygen and non-invasive ventilation,may be used to prevent reintubation in patients with low(e.g.,patients without comorbidities and with short durations of mechanical ventilation)and high risk(e.g.,patients>65 years and those with underlying cardiac disease,chronic respiratory disorders,and/or hypercapnia at the time of extubation)of reintubation,respectively.However,non-invasive ventilation used as a rescue therapy to treat established post-extubation respiratory failure could increase mortality by delaying reintubation,and should therefore be used very carefully in this setting.The oxygenation strategy to be applied in postoperative patients is different from the patients who are extubated in the ICUs.Standard oxygen after a surgical procedure is adequate,even following major abdominal or cardio-thoracic surgery,but should probably be switched to high-flow nasal oxygen in patients with hypoxemic.Unlike in patients experiencing post-extubation respiratory failure in ICUs wherein non-invasive ventilation may have deleterious effects,it may actually improve the outcomes in postoperative patients with respiratory failure.This review discusses the different clinical situations with the aim of choosing the most effective oxygenation strategy to prevent post-extubation respiratory failure and to avoid reintubation.